1. Field of Invention
The present invention relates to improvements in heat shields for internal combustion engines, and more particularly to heat shields having improved acoustic and heat dampening features.
2. Description of the Prior Art
Those skilled in the art will appreciate the issues involved in the dampening of undesirable acoustics and heat generated by automotive components, such as, for example, exhaust manifolds. Known heat shields that provide acoustic dampening may include multiple aluminum foil layers with embossments. Typically, the embossments are positioned in a staggered relationship to contact and space opposing foil layers. However, because the embossments directly contact the opposing foil layers, undesirable noise issues, such as rattle, may occur as a result of the vibrations of the embossments against the foil layers.
Other known heat shields comprise a three-layer structure including inner and outer metal layers with an intermediately disposed sound and heat shielding layer. Such three-layer heat shields have design restrictions that require the inner and outer layers to include different thicknesses so as to provide resonant frequencies that dampen undesirable acoustics. Even further, such three-layer heat shields undesirably require that the intermediately disposed sound and heat shielding layer includes a relatively large thickness in comparison to the inner and outer layers to fully damp the sound and heat to operable levels.
Thus, there is a need for an alternative heat shield that may overcome the undesirable fallbacks of traditional heat shields.